gpio: cadence: Add quirk for Axiado AX3000 platform

On the Axiado AX3000 platform, pinmux and pin configuration (such as
direction and output enable) are configured by the hardware/firmware
at boot time before Linux boots.

To prevent conflicts, introduce a platform-specific quirk triggered by
the "axiado,ax3000-gpio" compatible string.

When this quirk is active, the driver will skip its default
initialization of pinmux configuration and direction settings during
probe.

Co-developed-by: Tzu-Hao Wei <twei@axiado.com>
Signed-off-by: Tzu-Hao Wei <twei@axiado.com>
Signed-off-by: Swark Yang <syang@axiado.com>
Reviewed-by: Linus Walleij <linusw@kernel.org>
Link: https://lore.kernel.org/r/20260109-axiado-ax3000-cadence-gpio-support-v2-1-fc1e28edf68a@axiado.com
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com>

Author: Swark-Axiado

drivers/gpio/gpio-cadence.c

@@ -2,6 +2,7 @@
 
 /*
  * Copyright 2017-2018 Cadence
+ * Copyright (C) 2025 Axiado Corporation.
  *
  * Authors:
  *  Jan Kotas <jank@cadence.com>
@@ -31,10 +32,23 @@
 #define CDNS_GPIO_IRQ_VALUE		0x28
 #define CDNS_GPIO_IRQ_ANY_EDGE		0x2c
 
+struct cdns_gpio_quirks {
+	bool skip_init;
+};
+
 struct cdns_gpio_chip {
 	struct gpio_generic_chip gen_gc;
 	void __iomem *regs;
 	u32 bypass_orig;
+	const struct cdns_gpio_quirks *quirks;
+};
+
+static const struct cdns_gpio_quirks cdns_default_quirks = {
+	.skip_init = false,
+};
+
+static const struct cdns_gpio_quirks ax3000_gpio_quirks = {
+	.skip_init = true,
 };
 
 static int cdns_gpio_request(struct gpio_chip *chip, unsigned int offset)
@@ -141,6 +155,19 @@ static const struct irq_chip cdns_gpio_irqchip = {
 	GPIOCHIP_IRQ_RESOURCE_HELPERS,
 };
 
+static const struct of_device_id cdns_of_ids[] = {
+	{
+		.compatible = "axiado,ax3000-gpio",
+		.data = &ax3000_gpio_quirks
+	},
+	{
+		.compatible = "cdns,gpio-r1p02",
+		.data = &cdns_default_quirks
+	},
+	{ /* sentinel */ },
+};
+MODULE_DEVICE_TABLE(of, cdns_of_ids);
+
 static int cdns_gpio_probe(struct platform_device *pdev)
 {
 	struct gpio_generic_chip_config config = { };
@@ -165,6 +192,10 @@ static int cdns_gpio_probe(struct platform_device *pdev)
 		return -EINVAL;
 	}
 
+	cgpio->quirks = device_get_match_data(&pdev->dev);
+	if (!cgpio->quirks)
+		cgpio->quirks = &cdns_default_quirks;
+
 	/*
 	 * Set all pins as inputs by default, otherwise:
 	 * gpiochip_lock_as_irq:
@@ -173,8 +204,15 @@ static int cdns_gpio_probe(struct platform_device *pdev)
 	 * so it needs to be changed before gpio_generic_chip_init() is called.
 	 */
 	dir_prev = ioread32(cgpio->regs + CDNS_GPIO_DIRECTION_MODE);
-	iowrite32(GENMASK(num_gpios - 1, 0),
-		  cgpio->regs + CDNS_GPIO_DIRECTION_MODE);
+
+	/*
+	 * The AX3000 platform performs the required configuration at boot time
+	 * before Linux boots, so this quirk disables pinmux initialization.
+	 */
+	if (!cgpio->quirks->skip_init) {
+		iowrite32(GENMASK(num_gpios - 1, 0),
+			cgpio->regs + CDNS_GPIO_DIRECTION_MODE);
+	}
 
 	config.dev = &pdev->dev;
 	config.sz = 4;
@@ -240,9 +278,11 @@ static int cdns_gpio_probe(struct platform_device *pdev)
 	/*
 	 * Enable gpio outputs, ignored for input direction
 	 */
-	iowrite32(GENMASK(num_gpios - 1, 0),
-		  cgpio->regs + CDNS_GPIO_OUTPUT_EN);
-	iowrite32(0, cgpio->regs + CDNS_GPIO_BYPASS_MODE);
+	if (!cgpio->quirks->skip_init) {
+		iowrite32(GENMASK(num_gpios - 1, 0),
+			cgpio->regs + CDNS_GPIO_OUTPUT_EN);
+		iowrite32(0, cgpio->regs + CDNS_GPIO_BYPASS_MODE);
+	}
 
 	platform_set_drvdata(pdev, cgpio);
 	return 0;
@@ -260,12 +300,6 @@ static void cdns_gpio_remove(struct platform_device *pdev)
 	iowrite32(cgpio->bypass_orig, cgpio->regs + CDNS_GPIO_BYPASS_MODE);
 }
 
-static const struct of_device_id cdns_of_ids[] = {
-	{ .compatible = "cdns,gpio-r1p02" },
-	{ /* sentinel */ },
-};
-MODULE_DEVICE_TABLE(of, cdns_of_ids);
-
 static struct platform_driver cdns_gpio_driver = {
 	.driver = {
 		.name = "cdns-gpio",